1. Field of the Invention
The present invention relates to an arm structure in which an arm can be moved in a plurality of directions and each movement thereof can be locked, and to a holding device for a surgical instrument using that arm structure.
2. Description of the Related Art
In a surgical operation, a retractor 51 as shown in FIG. 17 for example is used. The retractor 51 is a surgical instrument for securing an operative field by inserting a tip thereof into an incision thereby to widen the incision. Usually, an assistant holds the retractor 51 or the retractor 51 is fixed by lacing a string through an opening 52 in a rear end.
However, if the assistant holds the retractor 51, there is a need to secure a staff for holding. Further, when the retractor 51 is desired to be moved, a surgical operator needs to give a detailed oral instruction. In a case that the retractor 51 is fixed by the string or the like, if the retractor 51 is desired to be moved, it is necessary to loosen the string once and to fix the retractor 51 again, taking a lot of trouble.
[Patent Document 1] Japanese Patent Application Laid-open No. 2004-290518
As a technique of this kind, there is disclosed in Patent Document 1 for example a device for mounting an attachment (for example, a suction unit for sucking and holding up a heart or a fork-shaped unit for pressing a pericardium (cardiac muscle surface) by two points across an anastomotic region) on a tip of an flexible arm. The flexible arm includes a flexible tube having a balled joint, a wire running inside the flexible tube. It is structured so that in a state that the wire is loosened, that is, in a state that the flexible tube can be bent freely, a position of the attachment is adjusted and in that state a handle is turned thereby to pull the wire, whereby a shape of the flexible tube is fixed by a tension of the wire, so that the position of the attachment is fixed.
However, in the flexible arm disclosed in Patent Document 1, an action to adjust the position of the attachment by bending the flexible tube and a handle manipulation for fixing and releasing of the shape of the flexible tube are separate actions.
Under the circumstances, an arm structure is desired in which a surgical instrument such as a retractor is held at a tip portion of an arm as well as the arm can be moved in a plurality of directions and each movement of the arm can be locked by a manipulation at hand. Further, such an arm structure is considered to be usable not only in a medical field but also in many other fields.